Compliments

Why is it that some things are considered compliments and other, similarly phrased things are not?

I like your eyes - compliment
I like your face - not a compliment

You have pretty hair - compliment
You have pretty eyebrows - kind of odd

Nice haircut - compliment
Nice toupee - not a compliment

Those are great glasses, are they new? - compliment
That's a great nose, is it new? - not a compliment

Time Flies!

No, really